In this Aug. 9, 2011 file photo, U.S. musician Prince performs during his concert at the Sziget Festival on the Shipyard Island, northern Budapest, Hungary. The enigmatic star flew into London on Tuesday, Feb. 4, 2014, at the start of a still-evolving string of dates in support of forthcoming album "Plectrum Electrum," recorded with all-female trio 3RDEYEGIRL. (AP Photo/MTI, Balazs Mohai, File)

MINNEAPOLIS (AP) – Prince’s sister says the superstar musician had no known will and she’s filed paperwork asking a Minnesota court to appoint a special administrator to oversee his estate.

Tyka Nelson filed the paperwork Tuesday in Carver County probate court. Prince died at age 57 on Thursday at his estate in suburban Minneapolis. No cause of death has yet been released.

Nelson is his only surviving full sibling.

Nelson says in her filing that an emergency exists because immediate action is necessary to manage Prince’s business interests. She’s asked that Bremer Trust, a corporate trust company, be named administrator.

With some $27 million in property and an outpouring of nostalgia over the pop star’s death, Prince’s heirs could stand to inherit a small fortune. The size of the fortune isn’t clear, and recent disputes suggest money was tight.